The background of the invention will be discussed in two parts:
1. Field of the Invention
This invention relates to systems for use in cataract surgery, and more particularly to a system for use in extracapsular cataract surgery.
2. Description of the Prior Art
In the performance of cataract surgery, an incision is made in the surgical limbus to provide access to the posterior chamber which contains the clouded lens which must be removed. During this surgery, a capsulotomy is performed, that is, incisions are made in the capsule to permit removal of the nucleus using one of several standard techniques.
As the surgery is performed, the surgeon utilizes equipment, tools and instruments such as suction cutters and irrigation and aspiration equipment. One such apparatus for use in this type of surgery is referred to as the McIntyre Coaxial Cannula System, this system including a handpiece with a connector configured for receiving one or more accessories. A first accessory includes separate inner and outer cannulae, mountable coaxially, with the inner needle providing for aspiration, and the passage between the inner and outer needles providing for irrigation.
The handpiece is connectable to first and second tubes, which are, in turn, connectable to infusion and aspiration systems, with appropriate passages within the handpiece suitably interconnecting the source to the appropriate needle. The infusion source usually includes a bottle of a solution, such as a balanced salt solution, connected by means of a suitable needle to the tubing, with the bottle at an elevated position for gravity feed. The aspiration source is usually suction equipment, such as a syringe, with both sources suitably controllable by the surgeon.
In the McIntyre Coaxial Cannula System, the outer cannula terminates in proximate relation to the inner(or longer) cannula, with this relation being fixed, unless other cannula are manually connected or reconnected. With this arrangement, in those instances when irrigation and aspiration are being accomplished simultaneously, close attention must be paid to the irrigation pressure and suction, both of which are occurring in physically proximate relation. For example, after removal of the nucleus, the capsular bag may be filled with cortical material which must be removed to cleanse the capsule for intraocular lens implantation. In such cases, irrigation and aspiration are used simultaneously, with aspiration sometimes accomplished in bursts of application of suction. The irrigation prevents collapse of globe as aspiration is performed.
Another such irrigation/aspiration apparatus is described in an article entitled "Simplified Extracapsular Cataract Extraction" by C. William Simcoe, M.D., published in the American Intra-Ocular implant Society Journal, Volume V, in April of 1979, the article appearing at Pages 154 and 155. In that article, Dr. Simcoe describes the creation of an outer cannula formed of Teflon tubing with an irrigating hole created in the tubing or sleeve by notching the side, the sleeve then being placed over a steel inner cannula or needle. With such devices, although side irrigation is intended, the tubing tends to leak, thus providing irrigation in the direction of the needle, that is, longitudinal.
It is accordingly an object of the present invention to provide a new and improved system for extra-capsular cataract surgery.
It is another object of the present invention to provide a new and improved extra-capsular system.
It is a further object of the present invention to provide a new and improved coaxial cannula system with provision for readily adjusting the spacing between irrigation and aspiration ports, as well as adjusting the direction of irrigation during use.
It is still another object of the present invention to provide a new and improved coaxial cannula system which includes provision for ready connection of other instruments.